There has been a great deal of research on the effect of changes in the price of alcohol on the consumption of alcohol. Changing the price of alcohol through taxation or other means has been proposed to reduce the economic costs of alcohol consumption and abuse. Much research has indicated that alcohol consumption is indeed responsive to price. However, little work has investigated the impact that alcohol price changes (or legal restrictions such as the minimum drinking age) have on the consumption of other drugs. That is, does this reduction in alcohol consumption come at the cost of increased use of marijuana, cocaine, or cigarettes? Or, does raising the price of illegal drugs lead to increased consumption of alcohol? If this is true, then policies aimed at reducing drinking must also incorporate their impact on illegal drug use and vice versa. This grant will examine the effect of drinking age laws and the price of alcohol on the consumption of marijuana, cocaine, and cigarettes by high school seniors using the well-known "Monitoring the Future" data set. In addition, it will look at the effect of the price of illegal drugs and cigarettes on the consumption of alcohol. That is, it will investigate whether alcohol and marijuana (and cocaine and cigarettes) are substitutes or complements for each other.